You are supposed to make proper cleaning every time you change the dye film ribbon.
There are simple steps to be followed as I will explain below.
You need a new cleaning Card and cleaning Pen.
Remove the cards and the film from the printer.
Remove the blue sticky roller from the printer is located towards the back side of the printer.
Remove the metal bar from the sticky roller and keep it in a safe place. Every new ribbon will come along with the new Sticky roller but it does not contain the metal roll.
clean the printer in automatic mode:
With the led open,
Go to control panel, select devices and printers. Right click on Pronto and select printing preferences.
You will be prompted to remove cards, film then the printer will initialize and request you to insert the cleaning Card.
With your new cleaning card open select yes on the printer and insert the cleaning card from the front.
Repeat this process for at least 5 times
Fold the card and place it on the main roller press move forward for about 15 seconds then press back also wait for at least 15 seconds.
Cleaning the printer Head.
With the printer powered off, carefully open the pen or thermal cleaning pen and clean the printer head.
Always clean the printer head in one direction not moving the thermal printer cleaning pen forth and back.
Final step is to insert the new blue sticky roller which comes along with the new ribbon.
Replace the ribbon and close the lid. The cleaning process is completed and you can do this every time you change the ribbon.